Web transactions may involve a web server device transmitting a web document to a client device. The web document may be formatted in accordance with a markup language, such as the HyperText Markup Language (HTML). The web document may define static content and how this static content should be presented on a web page rendered by the client device. In some cases, parts of the web page are not known until the web document is about to be transmitted to the client device or after this transmission takes place. Therefore, markup languages may also support dynamic content through embedded client-side scripts. These scripts may be delivered to the client device as part of the web document, and may be executed by a web browser on the client device. Such execution may result in the client device carrying out function calls, some of which may cause the client device to transmit requests for and receive the dynamic content from the web server device or other devices. In this fashion, dynamic content can be combined with the static content of the web document, facilitating more flexibility in the types of information that can be provided to client devices.
Nonetheless, client-side scripting may subject the overall web transaction to additional latency. Each time the client device executes a script that involves retrieving dynamic content over a network, the client device may wait for this content to arrive before it can be incorporated into the rendered web page. This delay may involve a round-trip time (RTT) of network propagation delay between the client device and the device providing the information, as well as processing delay at the latter device. Further, some client-side architectures block on such client-side requests (i.e., the client-side application waits for each request to complete before performing other requests or other operations), resulting in these requests being carried out serially. As a consequence, users may become frustrated with the amount of time that they have to wait for web content to load, while server devices are subjected to the overhead of serving multiple client-side requests per web document.